Probiotic combination for irritable bowel syndrome

The Impact of Probiotics on Biomarkers and Symptom Severity in Irritable Bowel Syndrome

Not applicable Interventional Sahlgrenska University Hospital · NCT07584278

This trial will test whether a daily probiotic capsule lowers symptom severity and affects gut transit time in adults with IBS.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment252 (estimated)
Ages18 Years and up
SexAll
SponsorSahlgrenska University Hospital Academic / other
Locations1 site (Gothenburg)
Trial IDNCT07584278 on ClinicalTrials.gov

What this trial studies

This is a double-blind, randomized, placebo-controlled trial testing a combination of two Limosilactobacillus reuteri strains (BG-R46™ and ATCC PTA 6475) in adults with IBS. 252 participants will be randomized 1:1 to take the probiotic or a matching placebo daily for 12 weeks, with a follow-up visit three months after treatment ends. Outcome measures include IBS symptom severity (IBS-SSS), oro-anal transit time, and a range of biological markers from blood, stool, saliva, and urine to explore mechanisms and predictors of response. Participants attend four in-person study visits for screening, randomization, end of intervention, and post-intervention follow-up while completing questionnaires throughout.

Who should consider this trial

Good fit: Adults (≥18 years) with IBS diagnosed by Rome V criteria, an IBS-SSS ≥75, BMI 18.5–35 kg/m2, able to give consent and complete Swedish questionnaires, and without excluded comorbidities or recent antibiotic/probiotic/opioid use are ideal candidates.

Not a fit: People with other gastrointestinal diseases, recent antibiotic use, current probiotic supplementation, major comorbid illnesses, or who cannot attend in-person visits are unlikely to benefit from participating.

Why it matters

Potential benefit: If successful, the probiotic could reduce IBS symptom severity and improve gut transit in some adults with IBS.

How similar studies have performed: Prior trials of certain L. reuteri strains have shown modest improvements in IBS symptoms, but this specific BG-R46™ plus ATCC PTA 6475 combination has not been tested in a large randomized trial.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Diagnosed with IBS according to ROME V criteria
* IBS-SSS greater than or equal to 75
* Adult over 18 years old
* BMI 18.5-35 kg/m2
* Able to understand the participant information sheet and willing to comply with the study protocol
* Able to give informed consent
* Able to complete the Swedish questionnaires

Exclusion Criteria:

* History of any gastroenterology disease including coeliac disease, heart, liver, neurological, or current psychiatric disease, diabetes, any surgery to the abdomen that affects intestinal function (not including cholecystectomy, appendectomy, ceasarean section).
* The use of opioids 1 month prior to screening and throughout the study
* The use of probiotic supplements from 14days before randomization and during the study (not including foods with probiotic components)
* Consumption of antibiotics 3 months prior to screening and throughout the study
* The start of any new drugs that affect the gastrointestinal tract or symptoms within the last month before the start of the study. As well as the start of new diets of psychological therapy as treatment for IBS symptoms.
* Participation in any medical research during the last month
* Clinically relevant lab abnormalities at the time of screening (fecal calprotectin greater than or equal to 150 ug/g as absolute cutoff. If calprotectin is between 50 - 150ug/g the decision is made on clinical judgement)
* Pregnancy, plan to become pregnant during the study, breastfeeding
* alcohol consumption \>14 units per week
* Use of recreational active drugs during 1 month before screening or during the study
* Use of medication that primarily affects bowel function, transit time, stool consistency 2 weeks before the intervention or during the 12 week intervention period

Where this trial is running

Gothenburg

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Irritable Bowel Syndromeprobioticirritable bowel syndomeibs symptom severityoro-anal transit timerandomized controlled trial
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.